1. Heat oven to 350 degrees F.
2. In a medium-size bowl, whisk together flour, baking soda and salt. Set aside.
3. In a large bowl, beat peanut butter and butter on medium speed 2 minutes, until creamy. Add brown sugar and 1/4 cup of the granulated, and beat 2 minutes. Beat in milk, egg and vanilla. Beat in dry ingredients until just combined. Stir in chips and nuts. Chill dough 15 minutes.
4. For each cookie, roll 2 teaspoons of dough into a ball and place on baking sheets 2 inches apart. With fork, flatten each ball into a 1 1/2-inch round, making a crosshatch pattern. Sprinkle a small amount of the remaining sugar over the top of each.
5. Bake at 350 degrees F. for 10 to 12 minutes, until lightly browned around edges. Let cool on sheets 1 minute. Transfer to rack; let cool.